Shoulder Screw

Hex Socket Shoulder Screws: Overview

Materials:

• Stainless steel (AISI 304/316 for corrosion resistance), carbon steel (heat-treated for strength), alloy steel (high-load applications), or titanium (lightweight, aerospace use).
• Surface treatments: Zinc plating, black oxide, or Dacromet coating for wear resistance and corrosion protection.

Manufacturing Process:

1. Cold Heading: Forms the screw head and shoulder section from wire stock.
2. Machining: Precision turning/grinding to create the smooth, cylindrical shoulder and threaded shank.
3. Hex Socket Milling: CNC machining of the internal hex drive (e.g., 2.5mm–10mm).
4. Heat Treatment: Hardening and tempering (for steel) to achieve optimal strength and toughness.
5. Surface Finishing: Coatings or passivation for corrosion resistance.

Key Production Considerations:

• Shoulder Diameter Tolerance: Tight control (±0.01mm) to ensure precise fit in bearing or pivot applications.
• Hex Socket Depth/Quality: Clean, burr-free socket for reliable tool engagement.
• Thread Alignment: Ensure concentricity between the shoulder and threaded shank.
• Surface Finish: Smooth shoulder surface (Ra ≤0.8μm) to minimize friction in rotating assemblies.

Applications:

• Machinery: Rotating shafts, gear linkages, and cam followers requiring axial alignment.
• Automotive: Pivot points in suspension systems, transmission components.
• Aerospace: Precision assemblies in actuators, control systems.
• Robotics: Joints and articulating arms needing low-friction rotation.
• Medical Devices: Adjustable clamps or surgical tool hinges.

Installation:

1. Tool Selection: Use a hex key (Allen wrench) matching the socket size.
2. Alignment: Insert the shoulder into the pre-machined bore for precise positioning.
3. Tightening: Apply torque gradually to seat the shoulder flush against the mating surface.
4. Torque Limits: Follow specifications to avoid stripping the hex socket or damaging threads.
5. Lubrication: Apply anti-seize compound in high-temperature or stainless-steel assemblies.

Advantages:

• Precision Alignment: Shoulder acts as a dowel, eliminating radial movement.
• Reduced Friction: Smooth shoulder surface minimizes wear in rotating parts.
• High Torque Capacity: Hex socket allows greater torque vs. slotted or Phillips drives.

Note:

• Avoid reusing screws in critical applications due to potential fatigue or socket wear.
• Match shoulder diameter to bore size for interference-free rotation.
• Use threadlockers in high-vibration environments to prevent loosening.